Columbia University's Department of Chemistry seeks funds to purchase a high-resolution electromagnetic mass spectrometer (e.g., VG Model 7035 MS and data system) which is capable of measuring mass spectra in the electron impact, chemical ionization, and field desorption modes; both positive and negative ions: metastable peaks can also be measured. The only usable instruments in the Department are a Ribermag D/CI 10-10 instrument and an old (one of the first) Finnigan 3000 instrument, both quadrupole models. Not a single high-resolution mass spectrometer exists in the entire university despite its high activity in research in the chemical and biological science fields. The principal investigator (Koji Nakanishi), whose major research interest has been in the isolation and structural studies of bioactive compounds at the sub-mg level, is sending all sensitive samples for molecular weight determinations or fragmentation studies to outside institutes. The research of the Columbia University scientific community, especially the investigators listed in this proposal, and those at the College of Physicians and Surgeons will benefit enormously from the acquisition of a modern, high-resolution mass spectrometer, a facility now completely lacking in Columbia University.